Plant care
Moore's Blechnumtemperature & humidity
Blechnum moorei
More about moore's blechnum
Ideal temperature for moore's blechnum
Temperature kills fewer moore's blechnum plants than you'd think. What kills them is the micro-climate within a normal-temperature room — a leaf pressed against single-glazed winter glass, the hot dry updraft directly above a radiator, the cold blast from an AC vent. The thermostat reading at 13–24 °C (55–75 °F) is fine; the spot you put the plant in matters more. Below roughly 13°C the damage starts — soft blackened patches, translucent leaves, sometimes overnight.
Cold tolerance & winter care
Moore's Blechnum is frost-tender (USDA 9–11, RHS H2). It cannot survive a frost, so in most of the US and UK it lives indoors year-round or summers outside and comes back in well before the first autumn frost — once nights drop toward 10-12°C is the cue, not the first frost warning. Acclimate it over a week when moving between indoors and out so the leaves do not shock.
Humidity for moore's blechnum
Moore's Blechnum sits happiest at around 55–80% relative humidity. High humidity is essential. Frond tips brown rapidly in dry indoor air below 50%. Place on a pebble tray filled with water, group with other plants, or use a humidifier. Avoid misting directly onto fronds as pooled water can encourage fungal spots. The usual low-humidity tell is crisp brown leaf tips and edges while the soil moisture is fine — a sign the air, not the watering, is the problem. If you need to raise it, the reliable methods are grouping plants together, standing the pot on a tray of damp pebbles (the pot above the waterline, never in it), or running a small humidifier in winter when indoor heating dries the air most. Misting is the least effective — it raises humidity for minutes, not hours.
Moore's Blechnum temperature & humidity — frequently asked questions
What temperature is best for moore's blechnum?
Moore's Blechnum grows best between 13–24 °C (55–75 °F). Keep it out of cold draughts, off freezing windowsills in winter, and away from the hot dry air directly above radiators — the extremes matter far more than the average room temperature.
How cold can moore's blechnum tolerate?
Moore's Blechnum starts to suffer below roughly 13°C. It is frost-tender and will be damaged or killed by a frost, so bring it indoors once nights fall toward 10-12°C.
What humidity does moore's blechnum need?
Moore's Blechnum prefers about 55–80% relative humidity. High humidity is essential. Frond tips brown rapidly in dry indoor air below 50%. Place on a pebble tray filled with water, group with other plants, or use a humidifier. Avoid misting directly onto fronds as pooled water can encourage fungal spots.
How do I raise humidity for moore's blechnum?
Group it with other plants, stand the pot on a tray of damp pebbles (kept above the waterline), or run a small humidifier in winter. Misting only helps for a few minutes, so it is the weakest option for a plant that genuinely needs more humidity.
Can moore's blechnum live outside?
Moore's Blechnum is rated for USDA zone 9–11 and RHS hardiness H2. Outside that range it must come indoors before the first frost — treat any outdoor stint as a summer holiday, not a permanent home.
More moore's blechnum care
In the UK? Keeping moore's blechnum warm in a UK home covers the radiator, single-glazing and heating-season humidity angle. Temperature and humidity are one piece. See the full moore's blechnum care guide, its cold-hardiness guide, and watering schedule — humidity and watering problems are easy to confuse.